GaN lateral PolarSJs: Polarization-doped super junctions

Wide bandgap semiconductors (WBG) offer the most compelling solutions for power electronics owing to their large breakdown electric field (E_b) and high carrier mobilities. The Baliga´s figure of merit (εμE_b³) of WBGs including GaN and SiC is ~100X higher than that of Si. On the other hand, super junction (SJ) diodes can break the limitation of the trade-off relationship between area specific-on resistance (R_{on, sp}) and breakdown voltage (BV) in conventional p-n junctions [1-2]. The combination of the super junction technology and GaN material would further boost the performance. Indeed, simulation results on GaN super junctions have shown great performance enhancement, but no practical solution for fabrication such device has been proposed and the challenge remains unsolved [3]. GaN natural super junction (NSJ) has been proposed and realized [4], but the high carrier densities of 2DEG and 2DHG layers result in severe electrical field crowding (similar to the field crowding near the gate on the drain side in HEMT) and the performances are far below expectation. An innovative technology to realize GaN super junction devices is highly desirable.